Rotary drill mechanism



June 24, 1930. E. v. CROWELL ROTARY DRILL MECHANISM Filed Sept. 12, 1928 2 yeets-shbet 1 i Q INVENTOR.

Era l 'mp el B? I 2 e ATTORNEY.

June 24, 1930. E. v. CROWELL ROTARY DRILL MECHANISM Filed Sept. 12,-1928 I 2 Sheets-Sheet 2 zwi' gif'waf v ATTORNEY.

. tom of the bore for uninterruptedly continuthe line 8 .3 of Fig. 1.

Patented June 24, 1930 l 1,767,350

i UNlTED STAT-ESPATENT OFFICE 1 :Ennv, .CRowE nonnoslanoii nEs, l I v i 'nott'ARY 'i nnitL Application filed September 12, 19 255 se -mam. 30;,44;

I This inventionirelates to rotary drillmeche A @It is further objectof the invention anism and has for its object to maintainpreto provide an efiicient but inexpensive condetermined pressure by the bit against the struction, and one which is extremely durable bottom of a well boreirrespective of the downand simple in its operation. I v y wardfeed of the-drill stem. More particu- Further objectsofl the. invention will be 5 larly the invention provides for maintaining readily. understood from the following deayieldable downward pressure by the drill scription of thesaccompanying drawings, in bit,-'either by fluid pressure or gravity so that. which Y J 1' i .in, theeventI of the bit' suddenly breaking Fig. 1 is a side elevation of the invention, through a relativelyhard formation it will partly-brokenaway and showing the drill bit 0 be immediately; lowered relativeto its drill telescopedrelative toits stem; stem without waiting for corresponding Fig. 2 is a similar view showing the-bit downward feed of the stem, and will thus reprojected downwardly relative to its stem. main-in operative engagement with the bot- Fig. 3 isanenlarged transverse section on i 65 ing the drilling operationthrough any rela- Fig. kis an enlarged transverse section on tivelyf soft stratum which may be encounthe line 44 of Fig.2. I I .tered'. a Y Y wFig. '5 is a View similar to Fig. 2 but show- .Itis a further. object of-the invention to .ing a modified construction.

preferably utilize the column of circulating Fig: 16. is a transverse section 'on the line 79 fluidin the string of drill pipe as. the medium 66 of Fig. 5. 1 a forrproviding a' yieldable downward pres- ;..-The:invention is applicable to any usual sure on the drill b1t; and to arrange the parts rotary drill bit, shown asa fish-tail bit 1, and so that during normal drilling a predeter the bit is-adapted'for suspension from a man- 5 mined'pressure on the bit may be maintained drilo2,either by a usual coupling 3 as shown 75 by the weight of simply the string of drill in Fig.1 1, or by an interposed string of drill pipe, with the yieldable pressureof either the pipe 4? and a drill collar 40 as shown in Fig. circulating fluidor gravity functioning to 5, with the 'mandril. arranged for telescopic lower'the bit relative to its stem only when movementrelative to a usual drill stem'comabnormal conditions, such as breaking prising the lengths of drill pipe 4. This 89 through to a relatively soft stratum, areen- "telescopic engagement includes a: rotarydrivcountered'm I ping connection between the stem and bit, and It is astill further object ofthe invention to for this purpose the mandril 2. may 'be exprovide for downward movementof the bit teriorly spline'd as shown at 5, for engagewithrelation to its stem while maintaining 'ment byscooperating. interior splines '6 on an 50 .yieldable pressure onthe bit.

the necessary rotary driving connection-beabutment sleeve7 which is'suspended from tween the drill pipe and the bit; and the inthe string of drill pipe 4 bya usual coupling 8. vention alsoprovides for packing off this The splinedmandril "2 is of appreciably telescopic engagement between the stem and greater length than the sleeve 7 so as to pro 40 bit so as to prevent leakage of the circulatvide for relative axial movement between the ing fluid; I bit and its stein", andsaid relative axial move- It is a still further object of the invention ment may be'limited 'inone direction by an to preferably arrange the telescopic-engage abutment at the upper end of the mandril ment between the stem and bit so as to'permit adapted for impingement by- "shoulders 10. 45 of the drill string being floated into the well formed bythe' upper ends 'of the splines 6, bore, and toalso provide for normal 'circulaandimay be limited in the-opposite direction tion of fluid during-operation 0f the drill, -by outwardly flaring thelower ends of splines with said circulating fluid preferably utilized 5 to form a shoulder '11, and correspondingly as the means for maintaining. the desired flaring the lower end of the bore of sleeve i 7 and its splines 6 as shown at 12, so that when (iii the drill bit telescopes relative to the string of drill pipe as shown in Fig. 1, the weight of the string will be exerted through sleeve 7 against the shoulder 11 of the mandril 2, for maintaining any predetermined pressure on the drill bit during the normal drilling operation.

Should the drill bit break througha relatively hard formation during the drilling op.- eration, so that a predetermined downward feed of the drill pipe will no lon-germaintain' the desired pressure of the bit against the bottom of the well bore, the pressure of the circulating fluid in the drill string is adapted to project the telescoped mandril 2 from the drill stem as hereinafter explained and as shown in Fig.2, iorthe weight of drillpipe 4 suspended from the =telescoped man-drills adapted to project the naandril as shown inFig. 5', thereby maintaining the desired pressure of the bit against the bottom ozt the bore by either fluid pressure or gravity means.

This projection of the bit 's limited by shoulders striking the abutment at the upper end of the nrandr-il, thesaid abutment being shown as a wear-resisting collar 9 which ispreterably yieldablymounted on the mandril for absorbing the shock of the impingement. Asan instance of this construction the mandril 2 may projectiu-pwardly beyond its splines 5 as shown at'15, with the collar 9 received on said projection and resting upon the splines 5, and a yieldable means shown as a rubber sleeve 16 received onprojection .15 and abutting against'the collar 9,1theyieldable sleeve 16 being preferably .held in place i A y a coupling 17 which may be threadedxo n the upper end of the mandril. isp-relerably mountedon the mandril {or packing off the, telescopic engagement between the drill bit and its stem, and preferably ;-;com1: rises .usu-al packing cups 19- 20' reversely mounted so as to pack off in opposite. directions. The coupling 17 may provide-a mount-ing for the lower packing cup 1 9 which has its lip 21 extendingdownwardly and received over a suitable shoulder 22 on the coupling 17, andthis packing cup may beheldin-place by a coupling 23 threaded onto coupling 17 and in turn forming amounting torthe upper packing cup 20 whicheseats on a shoulder '24 of the coupling 23, with its lip 21 extending upwardly and received over a cooperating shoulder 22 ofeither .acollar 25 or a collar. 25 shown in Figsl and 5 respectively, and which maybe interchangeably threaded onto'the endof coupling 23.

The mandril 2together with couplings 17 23and collar or 253 have a circulating bore 27 commun cating with the usual fluid discharge bore of the drill bit;and as shown in Fig. 5 the collar 25 forms an openbore for the circulating fluid, while as .shownin Fig. 1 the collar 25 supports a valve 30 which is adapted to close the bore 27 to the bore of the yond, its stem,

string of drill pipe 4, it being understood that mandril 2 together with abutment means 9- 16 and couplings 17-23 and collar 25 or 25 are adapted for free sliding fit in the drill pipe 4, while the packing 19-20 engages the bore of said drill pipe and thereby packs ofi between the drill bit and its stem, so that the entire column of circulating fluid in the string of drill pipe must flow through the bore 27 for discharge from the drill bit.

The valve 30 opensdownwardly from its .seat- 81 which may be threaded into the upper end ofcollar 25, and below the valve the bore of thecollar is preferably of stream-line section as shown at 32 for unobstructed flow of the circulating fluid past the open valve and thence downwardly through bore 127. The valve30 is'ad-apted for yieldable seating, and tor this purpose its stem '33 may project through a guide 34 extending upwardly from :the valve seat 31, with a spring 35 mounted on the stem between the guide and an abutment means shown as a nut 36' which is threaded on the upper end ofthe valves'tem.

The spring .35 .is comparatively strong, but will yield to permit opening of valve 30 re sponsive to the pressure of a column of fluid in the string of drill pipe, and as-a result of this tend-encyof the springto closethe value, together with the leaf-proof connection provided by packing 20 between the drill bit and its :stem,.it will beseen that during the drilling operation the column of circulating fluid will. exert appreciable. pressure against valve 30 tending to project the drill bit beand will then flow past the open valve .30 and through bore 27 for discharge at the .drill bit in usual manner. This yieldable pressure tending to project the drill bit is normally. overcome bythe Weight of the string of drill pipe resting on shoulder 11 and maintaining the drill bit telescoped as shownin Fig. 1, but when forany reason the string of drill pipe no longer maintains the desired pressure on the bit,-the yieldable fluid pressure against valve .30 projects-the bit as shown in Fig. 2 and thus maintains the desired drilling pressure irrespective of the downward feed of the drillpipe.

It will also be noted that the upwardly 1 r closing valve-30together with the leak-proof connection provided by packing 19 between the drill" bit and its stem, will completely shut-off the bore of the drill pipe during lowering of the. string into a well, and the column of fluid in the well below said closure means will thus provide for floating the string into the well.

Inthe, modification of the invention shown in Fig, 5 wherein theopen bored collar 25 replaces the valve 80, a suflicient length of drill pipe 4 is interposed between the bit 1 and the mandril 2 so that the weight of this pipe will provide the desired pressure tending to project the drillbit' beyond its stem.

- ing on shoulder 11 and telescoping the parts as previously described, and when for any reason the downward feed of pipe 4 is no longer sufficient to maintain the desired pressure on the bit, the weight of piped projects the bit and thus maintains the desired drilling pressure. Throughout the drilling operation the open bore 27 communicating with the bore of the drill pipe permits of free circulation of fluid for discharge at the bit.

I have thus provided extremely simple but practical means for floating a string of drill pipe into a well and then exerting the weight of the string against the drill bit during normal drilling, with the pressure of the circulating fluid adapted to project the drill bit beyond its stem and thus maintain the desired pressure on the drill, in the event of. the

downward feed of the drill pipe failing for any reason to maintain thesaid desired pressure on the drill bit; and I have also provided a construction whereby yieldable pressure on the telescopic drill bit may be maintained simply by gravity means without utilizing the pressure of the circulating fluid, when such a simplified apparatus is preferred.

I claim:

1. In combination, a drill stem, a drill bit, a telescopic connection between the stem and bit, means for discharging a circulating fluid through the stem and bit, means operable by the circulating fluid for yieldably projecting the bit relative to the stem, wear-resisting abutment means for limiting said projection of the bit, and means for cushioning said abutment. j

2. In combination, a drill stem, an internally splined sleeve suspended from the drill stem, an externally splined mandril cooperating with the internally splined sleeve for relative telescoping of said parts, and means for suspending a drill bit from the mandril, the mandril flaring outwardly at the lower ends of its splines so as to form a shoulder, and the lower end of the boreof thesplined sleeve being correspondingly flared for abutment against said shoulder.

3. In combination, a drill stem, a mandril adapted to telescope in said stem, means for 1 means for limiting said projection of the bit,

and means for cushioning said abutment.

5. In a drill stem, relatively axially telescopic parts having a splined engagement, the end of saidsplined engagement flaring to form abutment means for limiting relative axial movement of said telescopic parts.

6. Ina drill stem, relatively axially telescopic parts, a wear-resisting collar slidable on one of said parts, cushioning means for limiting-sliding of the wear-resisting collar on said part, and an abutment on the other of said parts adapted to engage the wear-resisting collar forlimiting relative axial movement of said telescopic parts.

In testimony whereof he has afiixed his signature.

ERD V. CROWELL.

suspending a drill bit from the mandril, a

wear-resisting collar on the mandril, cushioning means mounted on the mandril and abutting against the wear-resisting collar, a coupling connected to the mandril and abutting against the cushioning means, and an abutment on the drill stem adapted to engage the wear-resisting collar for limiting projection of the mandril relative to the drill stem.

4. In combination, a drill stem, a drillbit, a telescopic connection between the stem and bit, means for yieldably projecting the bit relative to the stem, wear-resisting abutment 

